2.4 Magnet Material

1. 2.4 Magnet Material A. Ghosh E. Barzi D. Dietderich

2. Materials Group • E. Barzi 2.4.1.1 Strand R&D • Strand Characterization • Ic, Is, RRR, M • Heat-treatment optimization • Extracted strand Test • D. Dietderich 2.4.1.2 Cable R&D • Cable Fabrication • Prototype Cable using new strand • Production Cable for Magnets • A. Ghosh 2.4.2 Conductor Procurement

4. Procurement Strategy Have a plan for conductor that ensures that there is sufficient material in the pipeline from OST for all the magnets to be fabricated in FY06 and FY07. Take advantage of the Conductor Development Program to advance the higher risk strand from being an R&D conductor to a “production” strand.

5. “Baseline Strand” • Rod Re-Stack Process, RRP 54/61 Design • 0.7mm diameter • Filament diameter ~ 70 mm • Jc in the range of 2400-3000 A/mm2 at 12T • RRR of stabilizer Cu > 100 • low field stability current Is ~ 1000 A and higher depending on reaction time/temperature 70 mm

6. Billet Characterization-Strand Stability IS IS

7. RRP HT Studies

8. Prediction of Short Sample Limits SRS01

9. High Field Short Sample Limits SRS01 BNL: Imax = 9780 A (490 A/strand) Bpeak = 12.4 T FNAL: Imax = 9630 A (480 A/strand) Bpeak = 12.2 T

10. Cable R&D

11. Cabling DegradationMinor Edge of 939R & 940R Two cables are in specification of thickness, width, and keystone angle • Strand Deformation at the cable edges • Filament Distortion • Simulate by rolling strands • Study effect of Filament Merging

12. Towards a more “flux-jump” stable conductor • For the RRP strand • Effective Filament Diameter Deff~ Sub-element Diameter • Deff scales inversely with increasing number of Sub-elements • Strand Stability increases with decreasing Deff • Increasing number of filament • Increases difficulty of wire processing • Packing difficulty, increased cold work of non-Sn components • Bonding issues wire yield Deff ~70mm 60 mm 50 mm 40 mm

13. Future RRP Strand 8079 7904 • At present the lower Jc ( > 2000 A/mm2) 91-design billet is moving into production  EFDA Order of 400 kg • Under CDP R&D this year, a high Jc 127-design billet is being processed (Nov-06) • Under FNAL core program a R&D billet using 120/127 design is being fabricated (Dec-06)

14. New R&D Design by OSTFNAL Core program Previous design New design (‘05) Newer design (‘06) 60/61 restack with spaced SE’s 120/127 restack with spaced SE’s 54/61 restack The new design has increased Cu thickness between subelements to reduce cabling impact on subelement merging.

15. Procurement Status3-30-06

16. Projected Inventory

17. RRP 54/61 –Piece Length • 250 kg of wire produced for LARP and CDP in the last 12 months, single billet yield is ~ 35kg • 93 % in lengths >1Km, 57% in lengths >3 km • With the following HT 665C/50 hrs • Average Jc(12T)=2880 A/mm2 • Average RRR= 189

18. Summary • Strand procurement of RRP 54/61 is proceeding on schedule. • There is sufficient conductor on hand for fabricating cable for the magnets. • Round and extracted strand testing is well established to qualify strand and cable • Test Data from the three labs are quite consistent • Heat treatment optimization studies used to improve strand stability • Cabling Degradation from filament shearing • Optimization of cabling parameters • Optimization of strand design • Rolled strand studies have been initiated for the new generation RRP conductor.